Constructing SiO₂-Supported Atomically Dispersed Platinum Catalysts with Single-Atom and Atomic Cluster Dual Sites to Tame Hydrogenation Performance

Construction and optimization of stable atomically dispersed metal sites on SiO₂ surfaces are important yet challenging topics. In this work, we developed the amino group-assisted atomic layer deposition strategy to deposit the atomically dispersed Pt on SiO₂ support for the first time, in which the particle size and ratio of Pt entities from single atom (Pt₁) to atomic cluster (Pt_n) and nanoparticle (Pt_p) on the SiO₂ surface were well modulated. We demonstrated the importance of dual-site synergy for optimizing the activity of single-atom catalysts. The Pt_1+n/SiO₂-N catalysts with the coexistence of Pt₁ and Pt_n showed excellent activity and optimized selectivity (99% for haloanilines) in halonitrobenzenes hydrogenation, while Pt₁/SiO₂-N catalysts were almost inactive in the reaction. Mechanism investigation indicates that the Pt_n site is beneficial for H₂ dissociation, and the Pt₁ site is energetically favorable for adsorption of the nitro group to complete the selective hydrogenation, which synergistically contributes to the optimized catalytic performances. This study provides a new strategy for constructing atomically dispersed metal species over the SiO₂ support and demonstrates the significance of the synergy of dual active sites for enhancing the catalytic efficiency.